try 
{
  document.execCommand("BackgroundImageCache", false, true);
} catch(err) {}

function InsertContent(tid, question) {
if(document.getElementById(tid).style.display == "none") {
	document.getElementById(tid).style.display = "";
	document.getElementById(question).className = "faqQuestion_on";	
	}
else {
	document.getElementById(tid).style.display = "none";
	document.getElementById(question).className = "faqQuestion";		
	}
}